An example of d3.behavior.zoom and d3.geo.path. By modifying the transform, the browser can rapidly redraw geographic features while panning and zooming, without the overhead of reprojection. This technique can be extended by combining with d3.geo.tile.
-
-
Save 1wheel/6414125 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| .overlay { | |
| fill: none; | |
| pointer-events: all; | |
| } | |
| .state { | |
| fill: #aaa; | |
| } | |
| .county-border, | |
| .state-border { | |
| fill: none; | |
| stroke: #fff; | |
| stroke-linejoin: round; | |
| stroke-linecap: round; | |
| } | |
| </style> | |
| <body> | |
| <button onclick="zoom.scale(1).translate([0,0]).event(zoomRect)">Zoom out</button> | |
| <button onclick="zoom.on('zoom', function(d){ console.log('no zooming!'); })">Disable zoom event</button> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script src="http://d3js.org/topojson.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500; | |
| var path = d3.geo.path() | |
| .projection(null); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var zoom = d3.behavior.zoom() | |
| .translate([0, 0]) | |
| .scale(1) | |
| .scaleExtent([1, 8]); | |
| var zoomRect; | |
| d3.json("/mbostock/raw/5925375/us.json", function(error, us) { | |
| var features = svg.append("g"); | |
| features.append("path") | |
| .datum(topojson.feature(us, us.objects.states)) | |
| .attr("class", "state") | |
| .attr("d", path); | |
| features.append("path") | |
| .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; })) | |
| .attr("class", "state-border") | |
| .style("stroke-width", "1.5px") | |
| .attr("d", path); | |
| features.append("path") | |
| .datum(topojson.mesh(us, us.objects.counties, function(a, b) { return a !== b && !(a.id / 1000 ^ b.id / 1000); })) | |
| .attr("class", "county-border") | |
| .style("stroke-width", ".5px") | |
| .attr("d", path); | |
| zoomRect = svg.append("rect") | |
| .attr("class", "overlay") | |
| .attr("width", width) | |
| .attr("height", height) | |
| .call(zoom.on("zoom", zoomed)); | |
| function zoomed() { | |
| features.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")"); | |
| features.select(".state-border").style("stroke-width", 1.5 / d3.event.scale + "px"); | |
| features.select(".county-border").style("stroke-width", .5 / d3.event.scale + "px"); | |
| } | |
| }); | |
| d3.select(self.frameElement).style("height", height + "px"); | |
| </script> |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment